Забыл уточнить, что в том js, где формируется контент так же для кнопок СТАРТ и СТОП:
document.getElementById('start').onclick = function () {
chrome.tabs.executeScript({code: "if (typeof start_new_bot != 'function') {alert('Please restart your browser and try again! / Перезагрузите браузер');}"});
chrome.tabs.executeScript({code: "start_new_bot(" + save_el.min_stavka.value + "," + save_el.max_stavka.value + "," + save_el.time.value + "," + document.getElementById('para').value + "," + document.getElementById('auto').checked + "," + document.getElementById('str1').checked + "," + document.getElementById('str2').checked + "," + save_el.min_per.value + "," + save_el.max_dohod.value + "," + document.getElementById('demo').checked + ");"});
window.close();
}
document.getElementById("stop").onclick = function () {
chrome.tabs.executeScript({code: "end();"}),
window.close()
}